msem-instigator

Seaside Citadel enters the battlefield tapped.
{T}: Add {G}, {W}, or {U}.

({T}: Add {U}.)
As Seaside Grotto enters the battlefield, you may pay 1 life. If you don't, Seaside Grotto enters the battlefield tapped.
Basic lands you control have “{T}: Add {U}.”

({T}: Add {G} or {U}.)
Secluded Cascade enters the battlefield tapped unless you control two or more basic lands.

As Secluded Courtyard enters the battlefield, choose a creature type.
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type or activate an ability of a creature source of the chosen type.

{T}: Add {C}.
{T}, Reappropriate: Add {G} or {W}. (Exile exactly two cards from your hand and/or graveyard.)

When Secluded Monument enters the battlefield, choose a color.
Whenever you cast a spell of the chosen color, Secluded Monument becomes a 5/5 Golem creature until end of turn.

({T}: Add {W} or {U}.)
Whenever Sedate Tundra becomes tapped, you lose 1 life unless you control two or more basic lands.

When Seductive Seashell enters the battlefield, target player mills two cards.
{2}, Sacrifice Seductive Seashell: Target player mills four cards.

({T}: Add {G}.)
Seedshrine enters the battlefield tapped.
When Seedshrine enters the battlefield, you may put a +1/+1 counter on target creature.

{T}, Pay 1 life: Add {B} or {G}.
{1}, {T}, Sacrifice Seedy Bar: Investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

{T}: Add {R} or {W}.
{R}{W}, {T}: Target creature gains first strike and haste until end of turn.

Equipped creature has hexproof and distorted. (It can be blocked by tapped creatures but not untapped creatures.)
Equip {1}

When Seeker's Guardian enters the battlefield, reveal the top card of your library.

Equipped creature gets +1/+1.
At the beginning of your end step, if you don't control a creature, create a 1/1 white Human creature token and attach Seeking Sword to it.
Equip {1}

Creatures with power less than Seer of the Hunt's power can't block it.

Whenever you scry, draw a card.

{3}, {T}: Scry 3.
{5}, {T}: Fateseal 3.
{7}, {T}: Draw two cards.

{T}: Add {C}.
{7}, {T}: Create a 2/2 colorless Spirit creature token.

Equipped creature gets +1/+0 for each colorless creature you control.
Equip {1}

Equipped creatures you control get +1/+1.
You may activate equip abilities any time you could cast an instant.
Equip {2}

{3}: Sellsword Contraption becomes the creature type of your choice until end of turn.

When Sentient Contraption enters the battlefield, create a 1/1 colorless Thopter artifact creature token with flying.

Soldiercycling {1}{W}, Wizardcycling {1}{U}, Zombiecycling {1}{B}, Warriorcycling {1}{R}, Elfcycling {1}{G} ({1}{G}, Discard this card: Search your library for an Elf card, reveal it, and put it into your hand, then shuffle.)
Sentinel of Latter Days is every creature type as long as it's in your library.

Equipped creature has vigilance and reach.
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

{T}: Add {C}.
{T}, Reappropriate: Add {U} or {B}. (Exile exactly two cards from your hand and/or graveyard.)